<template>
  请输入姓名：<input type="text" v-model="username" />
  <div>姓名是：{{ username }}</div>
  <br />
  <input type="text" v-model.number="n1" /> 
  + <input type="text" v-model.number="n2" /> =
  {{ n1 + n2 }}
</template>
<script setup>
import { ref } from "vue";
const username = ref("zhangsan");
const n1 = ref(1);
const n2 = ref(2);
</script>
